1. Field of the Invention
The present invention relates to portable cleaning systems for on-site cleanup, especially for cleaning debris at toxic waste sites.
2. Description of the Related Background Art
Equipment to clean up a toxic waste site preferably should have several characteristics. First, it should be portable, and preferably should be able to be loaded and unloaded from standard truck trailers, or else built onto a truck bed or trailer.
Second, it should effectively surface clean debris such as 55-gallon drums, machinery, bricks, plastic, or rocks. It should remove organic chemical pollutants such as PCB, DDT, lindane, or lead, mercury, or other metals and metal compounds, which are dissolved in oily surface films or bonded to solids by hydrocarbon contamination.
Third, the cleaning system and equipment should not generate polluted residue in any great quantities, as this would destroy the purpose of cleaning up the toxic waste.
Several prior-art devices are known for cleaning drums, metal parts, etc, but none of these matches the capabilities of the present invention.
Commercially-available drum washing equipment and commercial beverage can washers are not available as trailer mounted units, and cannot cope with the large amounts of soil and mud mixed with the debris at a typical toxic waste site.
Hand-held, high-pressure water lasers are portable and are not easily clogged, but are not safe and generate large amounts of residue-containing wash water.
Degreasers are not environmentally safe, are not rugged enough, and generate a great deal of residue.
Steam cleaning equipment is dangerous to operate and generates residues.
Freon spray-wash equipment has all the drawbacks of the others, except that it is transportable.
A portion of a paper by M. L. Taylor, M. A. Dosani, and J. A. Wentz, et al, described a field demonstration of a device related to the present invention, was presented at the Second Forum on Innovative Hazardous Waste Treatment Technologies in Philadelphia, Pa. in May 1990.
An Abstract, Attachment C, was published in the Proceedings of the 18th Annual RREL Research Symposium, EPA/606/R-92/028, April 1992. The authors are listed as Michael L. Taylor, Majid A. Dosani, and John A. Wentz, Avinish N. Patkar, and Naomi P. Barkley.
Attachment D of the paper is entitled Transportable Debris Washing System: Field Demonstration Results and Status of Full-Scale Design, by Michael L. Taylor, Majid A. Dosani, and John A. Wentz, and Avinish N. Patkar of IT Corp., and Naomi P. Barkley and Charles Eger of the EPA. This was presented at the Third Forum on Innovative Hazardous Waste Treatment Technologies: Domestic and International, held in Dallas, Tex. on Jun. 11-13, 1991.
An Abstract was published in the Proceedings of the 18th Annual RREL Research Symposium, EPA/606/R-92/028, April 1992. The authors are listed as Michael L. Taylor, Majid A. Dosani, and John A. Wentz, Avinish N. Patkar, and Naomi P. Barkley.
The attachments C and D describe the choice of BG5 as a non-ionic, non-toxic, low-foaming surfactant following bench trials of various surfactants by high-pressure spray, turbulent wash tank immersion, and air-drying. Surface wipe tests, before and after the wash and spray, were used to evaluate the surfactants.
As disclosed in the attachments, a pilot-scale test device was constructed which was disclosed to have a 300-gallon spray tank, a 300-gallon wash tank, a surfactant holding tank, and rinse water holding tank, an oil/water separator, and a solution-treatment system with diatomaceous earth filter, activated carbon column, and an ion-exchange column.
The spent surfactant and rinse water were treated after the debris clean-up in a water treatment system that removed the pollutants.
The attachment C describes the plan to use a heavy duty basket drum lifted by crane into a tank, immersion in "high-turbulence" washing solution, and tumbling action. It also discloses a continuous water treatment system for cleaning during the debris cleaning operation, and a heating system. Attachment D describes an oil/water separator and rotating basket drum, a single wash/spray/rinse chamber, and semi-automatic operation. It discloses plans to use an "innovative system" to "directly impact" detergent spray onto the debris, but it does not disclose any specifics of that system. No details of the spray system contemplated by the inventors were disclosed.
A paper entitled "Field Experience With a Full-Scale Debris-Washing Process" was presented at the Air and Waste Management Association's 87th Annual Meeting and Exhibition, Jun. 19-24,1994, Cincinnati, Ohio, by authors Michael L. Taylor and Majid A. Dosani of the IT Corporation, Cincinnati, Ohio and Naomi P. Barkley and Donald E. Sanning of the U.S. Environmental Protection Agency, Risk Reduction Engineering Laboratory, Cincinnati, Ohio.
An article entitled "Field experience with a full-scale debris-washing process" was published by Computer Methods and Advances in Geomechanics, Siriwardane & Zaman (eds), 1994 Balkema, Rotterdam, ISBN 90 5410 380 9. The authors listed are M. L. Taylor, M. A. Dosani and H. Davidson of IT Corporation, Cincinnati, Ohio and Pittsburgh, Pa., USA.